Sifting Through our Hand Collections

Every week we decide to find a few trails that are not near our regular sites to do some hand collecting. This week in Kejimkujik National Park we decided to go to Beech Grove Trail. When we got there we found out that the trail runs parallel to a river so before we got to hand collecting we did some aquatic collecting. After getting our feet wet we were visited by a few people that were interested in what we were doing. We told them all about BIO and the BIOBus, we told them about what we were doing in the park and what we were doing right then and there with our rain boots and nets. They seemed very interested in what we had to say and thanked us for the free bookmarks that BIO provided us to give out. After making some new friends we head back to the bus to change into our hiking gear and gather all our equipment for hand collecting. Each crew member carries with them four ethanol vials to store insects they catch, an aspirator to suck up insects and a piece of collecting equipment of their choosing, such as sweep nets and sifting trays.

Martin Zlatkin aspirating insects from a sifter at Saint-Louis Cape in Kouchibouguac National Park

Sifting trays are my favorite method of searching for insects, probably because I used them so much when I was on my field course in Vietnam. A sifting tray is very simple to use and it does exactly what the name implies, it sifts. To use the sifting trey I grab a large hand full of leaf litter and drop it in to the sifter, I shake the leaves around which causes the smaller pieces of dirt and insects to fall in to the lower compartment of the tray. After I’ve shaken the leaves around for about 2 minutes I take the leaves off and look at what has fallen into bottom section. At that point I pick through the dirt to find all the insects that fell through the sifter. I find the insects that crawl on the ground to be much more interesting than the insects in the air, that’s why I use a sifter rather than a sweep net. I’ve never seen the appeal of catching many mosquitoes and maybe 5 interesting flies or bees. Sifting always yields something new for me; a gigantic spider, a quick springtail, or an interesting looking beetle. I find hand collecting events are always the most interesting part of a day.

Fun in the Sun at Merrymakedge Beach

Fun in the Sun at Merrymakedge Beach

The sky was gloomy as raindrops fell onto the BIObus and woke us this morning. Hoping the weather would clear, we travelled to our farthest sites near Big Dam Lake. The sampling sites are very different in vegetation, but are similarly exhausting to locate; both require GPS coordinates and bushwhacking to gain access. The day had turned hot and humid as we hiked to the bus after performing site maintenance, so we travelled to Merrymakedge Beach to spend the rest of the afternoon.

A large Luna Moth found on the side of the night sheet at Merrymakedge Beach in Kejimkujik National Park, NS.

Here we swam in the sparkling freshwater of Kejimkujik Lake and enjoyed basking in the sun. The beach was covered in fine pebbles, turning to larger stones as the water deepened further from the shore. Flipping over few choice rocks and exposing their underside, we were able to find a lot of insect larvae clinging to the hard surfaces; they were hiding between the stones and underlying substrate. We chose to aquatic collect with this discovery. Among the most commonly encountered were mayflies, which scuttled across the rock surfaces. There were also Caddisflies, a few differing beetles, and many tiny water fleas.

We remained at Merrymakedge Beach long after sunset to do a night sheet; a nocturnal UV-powered trap to collect insects attracted to the glow. This night, the insects by the lake were extremely active and the trap was buzzing loudly with swarming black flies and larger Caddisflies (Order: Trichoptera). Caddisfly adults emerge from the aquatic larvae encountered earlier; they typically make silken cases underwater for protection. The silk is webbed together, and particles adhere to it, camouflaging the insect. They can be made with twigs, small pebbles, leaves or other debris in the water. These cases catch the water current; the web filters small particulate matter that is fed on. The cases also act as a useful indicator of which caddisfly species they are. Conversely, adults look so similar that their appearance alone cannot discriminate it from other species of the order. It is remarkable that aquatic Trichoptera larvae found earlier can be so distinctive, but molt into morphologically identical adults.

One of the most noteworthy insects we encountered on the night sheet was a large Luna Moth. This beautiful moth (which also graces the sides of the BIObus) is mint green in colour, with a white furry body and feathery antennae. It rested motionless on the sheet, lethargic because of the cold night temperature. After collecting insects found on the night sheet we anxiously drove back to our campsite, eager to jump into out sleeping bags and go to bed after a long day spent outside.